Two-temperature refrigeration system using two refrigerants



&4835842 L. A-. PHILIPP TWO-TEMPERATURE REFRIGERATION SYSTEM USING TWOREFRIGERANTS Oct. 4, 1949.

Filed Jan. 2, l948 2 Sheets-Sheet l 2 6 7 ZZ n 2 IN V EN TOR.Lflw/EEA/CE fi- PH/L PP BY Oct. 4, %949. PHILIPP & 9

` TWO-TEMPERATURE REFRIGERATION SYSTEM USING TWO REFRIGERANTS Filed Jan.2, 1948 2 Sheets-Sheet 2 INVENTOR. WEEA/CE H- PH/L/PP 24' I e" !fly/;MIr

Hr TORNE'V Patented Oct. 4, 1949 STTES &483.842

TWO-TEMPERATURE REFRIGERTION SYSTEM USING TW@ REFRIGERANTS ApplicationJanuary 2, 1948, Serial No. 145

Claims. (ci. 62-11@ i This invention relates to refrigerating apparatusand more particularly to such apparatus as is designed to operate at lowtemperatures.

In storing and preserving confections, such as ice cream, in a rozencondition it has been found that package ice cream including chocolatecovered types require a lower temperature than dip ice creams to bemaintained in proper frozen condition and accordingly it is bothdesirable and economical to maintain different temperatures in therefrigerator which stores such confections.

It is an object of the present invention to provide an improvedarrangement for maintaining confections in their frozen condition byutilizing a single refrigerant evaporator to refrigerate twocompartments and proportion the evaporator so that it has greaterrefrigerated surface per square inch about the walls of one compartmentthan the other and to circulate refrigerant through said evaporator byintroducing same into said evaporator where it will pass about walls ofthe compartment which has the greater refrigerated surface about thewalls thereof and to utilize as a refrigerant a mixture of refrigerantsof difierent boiling points so that the portion of the evaporator whichis the first to receive refrigerant will be the colder portion.

Further objects and advantages of the pzsent V invention will beapparent from the following description, reference being had to theaccompanying drawings, Wherein a preferred form of i" preserving ofconfections such as ice creams and other foods to be frozen. The cabinetmay comprise a sheet metal casing 22 and a sheet metal liner 24.suitable heat insulation 26 is preferably provided between the casing 22and the liner to decrease heat leakage into the cabi net. At one end ofthe cabinet 20, the casing 22 and the liner 24 have theircorrespondingbottom walls ofiset upwardly providing a machinerycompartment 21 within the cabinet outer casing to receive a refrigerantcondensing element, designated generally by the numeral 28. Extendingupwardly from the cabinet ofiset wall between the ends of the cabinet isa partition 2@ which divides the interier of the cabinet formed by theliner into a relatively large deep storage compartment 38 and arelatively small, shallow storage compartment 32. In the top wall of thecabinet, as at 36, access openings to the storage compartments 30 and 32are preferably closed by removable closure members 35. In the presentrefrigerator the compartments 3@ and 32 are cooled to differenttemperatures. Compartment 30 may be cooled to a low temperature suitablefor preserving foods like ice cream of the dip type whereas compartment32 may be cooled to a lower temperature for storing chocolate coveredice creams and other package ice creams which require lower temperaturesthan dip ice cream.

In accordance with my invention I provide a single refrigerantevaporator 40 for the refrigerator and arrange this evaporator to absorbheat from both of the cabinet compartments 30, 32 in a manner such thatthe compartments are cooled to different low temperatures. As shown, theevaporator M is preferably in the form of a coil or conduit and ispreferably arranged in sinuous form along the side. ends and ofiset wallof the cabinet liner 2 3 to absorb heat from walls of the liner.Preferably, the evaporator coil 40 is attached to the exterior surfaceof the liner :e out of the way of foods to be stored in thecompartments. Any well known suitable cement may be used to secure theevaporator coil ti) to the liner 24 in good heat transfer relationshiptherewith.

In the machinery compartment 21, the refl-igerant condensing element 28comprises, in general, a motor-compressor unit 46 and a refrigerantcondenser 48. A refrigerant receiver 50 may be provided and also may belocated in the machinery compartment 26. Liquid refrigerant is suppliedfrom the condenser 48 to the refrigerant receiver 50, whence therefrigerant is delivered by a capillary or flow controlling tube 52 tothe inlet end of theevaporator 40. As is well known, the capillary tube52 serves to supply proper amounts of the refr'gerant to the evaporatorto obtain desired temperatures. From a refrigerant accumulator 54 at theoutlet end of the evaporator 40, gaseous refrigerant is returned to themotor-compressor unit 46 through a return conduit 56. A portion of thecapillary tube, as at 58, is preferably arranged in good heat absorbingrelationship witha portion of the return cor duit 58 so as to cool therefrigerant en route to the evaporator 40 for increased refrigeratingemciency. As shown in Fig. 1, the portion of the capillary tube 52 whichis in heat transfer relationship with the return conduit 50 preferablyextends through or is surrounded by an insulating casing 60. This casingmay be made of rubber or of any other suitable heat insulating material.From the insulating caslng 60, the capillary tube 52 and the return line56 extend through the ofiset, cabinet bottom wall which separates themachinery compartment 26 from the food storage compartments 30, 32.

In order to maintain different low temperatures in the compartments 30and 32 with the single evaporator 40 without use of mechanical or othercontrol devices, I provide a mixture of two miscible refrigerants havingdifferent boiling points. While various types of refrigerants may beused to provide this mixture I combine two refrigerants, one of which isdichlorodifluoromethane (CC12F2) commonly called (F-12) and the other ismonochlorod'flouromethane (CHClF2) commonly called (F-22). These tworefrigerants have different boiling points with (CClzFz) having a lowerboiling point than (CHClFz). The proportions of these refrigerants byweight are approximately 40% (CC12F2) to approximateiy 60% of(CI-IClFz). The refrigerant flow through the evaporator 40 is inthedirection of the arrow shown in Figs. 2 and 3. As will be noted inFigs. 2 and 3 the parallel straight runs of the evaporator 40 are closertogether about the side walls of the liner portion forming compartment32 than about the side walls of the liner part which forms thecompartment 30. Also the liner part which forms the bottom walls ofcompartment 32 has a portion of the evaporator 40 attached thereto.Accordingly the walls of compartment 32 have the greater refrigeratedsurface per square inch of liner surface.

When the refrigerant is introduced into the evaporator 40 the morevolatile refrigerant of lower boiling point will evaporate in thatportion of the evaporator 40 adjacent the evaporator inlet or in theportion of the evaporator which principally cools the compartment 32 soas to cool this compartment to the desired temperature. The other, orless volatile refrigerant of higher boiling point, will pass along andevaporate principally in that portion of the evaporator 40 which isassociated with compartment 30 and thus will cool this compartment tothe desired temperature and at a temperature above that of compartment32. Accordingly, I attach the evaporator coil 40 to the liner 24 so thata desired length of the coil starting with the inlet end thereof isarranged to extend continuously along the bottom and three sides orsurface portions of the liner which form th compartment 32. Theevaporator coil 40 then extends on the other side of the partition 28from the compartment 32 and is arranged in heat absorbing relation withthe wall portions of the liner forming the relatively higher temperaturecompartment 30. Thus, it will be seen that the refrigerant of relativelylow boiling point will boil out in the anterior portion of the coi140and the refrigerant of relatively high boiling point will boil out inthe posterior portion of the coil 40 cooling compartments 30, 32 todifferent desired temperatures. In other words the temperature at whichvaporization of the refrigerant of low boiling point takes place will belower p as a result of which heat absorption is greater about thecompartment 32.

From the foregoing description it will be noted that I have arranged forthe cooling of two refrigerator compartments to different temperaturesby a single evaporator using a. mixture of refrigerants of differentvolatility and boiling points. It will be appreciated that by the use ofa mixture of two refrigerants of the proper proportion that two storagecompartments may be maintained at different temperatures by a singleevaporator without need of pressure differential devices or othercontrol elements. It will also be noted that the liner portion whichforms the compartment 32 has a greater refrigerated surface per squareinch than the portion which forms the compartment 30. By having agreater refrigerated surface and by evaporating the refrigerant of lowboiling point about the liner portion which forms compartment 32 thiscompartment will be maintained at a lower temperature than compartment30.

Although only a preferred form of the invention has been illustrated,and that form described in detail, it will be apparent to those skilledin the art that various modifications may be made therein withoutdeparting from the spirit of the invention or from the scope of theappended claims.

I claim:

1. Refrigerating apparatus comprising a cabinet having a liner, arefrigerating system including a refrigerant evaporator and arefrigerant condensing element operatively connected together, saidevaporator having an inlet section in heat exchange relation with afirst portion of said liner and another section in heat exchangerelation with a second portion of said liner, and a mixture ofrefrigerants of different boiling points in said system with therefrigerant of low boiling point being proportioned with respect to theevaporator section in heat exchange relation to said first portion ofsaid liner to substantially evaporate in its passage through said inletsection.

2. Refrigerating apparatus comprising a cabinet having a. liner, arefrigerating system including a refrigerant evaporator and arefrigerant condensing element operatively connected together, saidevaporator having an inlet section in heat exchange relation with afirst portion of said liner and another section in heat exchangerelation with a second portion of said liner, the first portion of saidliner having a greater refrigerated area per square inch than saidsecond portion, and a mixture of refrigerants of different boilingpoints in said system with the refrigerant of low boiling point beingproportioned with respect to the evaporator section in heat exchangerelation to said first portion of said liner .to substantially evaporatein its passage through said inlet section. 4

3. Refrigerating apparatus comprising a cabinet having a liner, arefrigerating system including a refrigerant evaporator and arefrigerant condensing element operatively connected together, saidevaporator having an inlet section in heat exchange relation with afirst portion of said liner and another section in heat exchangerelation with a second portion of said liner, the first portion of saidliner having a greater refrigerated area per square inch than saidsecond portion, and a mixture of refrigerants of different boilingpoints in said system.

4. Refrigerating apparatus comprising a cabinet including sheet metalmaterial forming wails of a relativeiy large and a relatively smallcompartment, a refrigerating system including a refrigerant evaporatorand a refrigerant condensing element operatively connected together,said evaporator having portions in engagement with walls of said sheetmetal material about both compartments with a greater effective heatabsorbing surface per square inch of material being placed about saidrelatively small compartment, and a mixture of refrigerants of difierentboiling points in said system.

5. Refrigerating apparatus comprising sheet metal material forming wallsof a cooling zone, sheet metal material forming walls of a freezingzone, conduit means arranged for conducting refrigerants about walls ofsaid zones, said means having its inlet end in heat absorbing'relationship with the material forming walls of said freezing zone andhaving greater heat absorbing area per square inch about said freeingzone than about said cooling zone, a refrigerant condensing elementoperatively connected with said means and a mixture of refrigerants ofdifierent boiling I points in said element and said means.

LAWRENCE A. PHILIPP.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

